The skin on the palms and the soles of the feet is 4 mm thick and the thickest skin in the body, the heel portions of the feet being the thickest portions. It’s also got the most sweat glands than in any other area.

In space, no one can hear you cry. Because you can’t. Astronauts are unable to cry properly because there is no gravity and tears cannot flow properly as they would on Earth. It is possible to produce tears in space – but they would leave the eye and float around.